ASPHALT EXPERT SYSTEM ®© FAQ:
- FUNDAMENTAL MISTAKES IN PREVAILING RATIONAL -
No CONSISTENCY, WHY?
· The Optimum Mix Design Is Necessary But Not Sufficient Condition For Consistency. Uniformity In Production, Laying Down, And Compaction Would Secure Functional Long Life-Cycle Asphalt Layer.
Let’s Start From The Very End Backwards...
· Quality Of Optimum HMA Would Be To Some Extent Affected By Temperature Segregation If One Is Not Aware/Plays Down/Ignores Anti-Segregation Measures
· The Consistence Could Be Severely Affected By Sudden Changes Of ‘Environment’ Parameters Such As: Humidity, Wind-chill Factor, Temperature, Unless Job Mix Formula (JMF) Is Re-optimized According To RATIONAL ASPHALT TECHNOLOGY®© EXPERT KNOWLEDGE BASE CRITERIA
· The ‘Target’ Grading Would Fluctuate During HMA Production and Handling Unless It Is In ‘Real Time’ Re-optimized Using The Latest Optimization Tools.
· Optimum ‘SPATIAL’ Mix Design Is Possible, ONLY IF One Has A Necessary ‘Know-How’ On Dynamic Prioritization Of Functional Constituents, And The Technical Means – i.e. An Adequate OPTIMIZATION SOFTWARE - To Carry Out The Job. Otherwise, One Paves The Way For CUMULATIVE ERROR And FAILURE.
CONSISTENCY IS A WISH
BUT VERY OFTEN NO MORE THEN SPORADIC ACHIEVEMENT IF ONE DOES IT THE ‘
EXPLANATION- EXAMPLE I
How One Can Achieve Consistency/CONTROL Using MASS/Simple VOLUMETRIC ASPHALT MODEL?
FIRST REALITY: Sieves Do Not Recognize Mass
But Geometrical/Volumetric/Spatial Properties Of The Aggregate Particles
(As Clearly Shown On Picture Bellow - Up Left)
SECOND REALITY: All Aggregate Particles Have Pores - That Is Nature’s Reality
A Sieve Cannot DIFERENTIATE IF PARTICLES ARE WITH/WITHOUT PORES.
Therefore, Pores Must Be Included In Calculation.
(As Clearly Shown On Picture Bellow - Down Right)
THIRD REALITY: ‘COMPETITION FOR SPACE’
As Anywhere Else In The Nature,
Any Complex System Always Tends To Achieve A New
THERE ARE DIFFERENT DENSITIES OF PHYSICAL INPUT – CONSTIYUENTS- IN ONE AVERAGE HMA:
DIFFERENT AGGREGATES, BINDER, MODIFIERS…
IN EACH MOMENT THOSE REAL DENSITIES MUST BE KNOWN AND TAKEN INTO ACCOOUNT
(As Clearly Shown On Picture Bellow - Up Right)
EXPLANATION- EXAMPLE II
How One Can Achieve Consistency/CONTROL If Doesn’t Know How Much Of The ‘Space’ Corresponds To Specific Grading Structure,
And How Much That ‘Space’ Would Change When Grading Curve Changes From The Original Curve From Whatever Reason?
One Must Know The Law Of Skeletal ‘Spatial’ Packing To Begin With…
On Picture Bellow One Can Glimpse Complexity Of The Problem.
Theoretically, A Billion Grading Curves Is Possible To Insert Between ‘0’ And ‘NMPS’.
Everybody Knows, ‘Fuller’s Curve n=0.45’ Is Just A Broad Guideline, And In Many Cases It Doesn’t Work.
‘SUPERPAVE Folks Also Know That Many Of Their Expensive Stuff DO NOT WORK.
SO, WHAT DOES WORK?
With Every Change In Gradation, The Surface Area (SA) Also Changes, Especially In A Sensitive Filler/’Fine’ Fines Area, Which ‘Consume’ 55-70% Of Available Binder.
In Most Cases Maximum Skeletal ‘Spatial’ Packing Is The Optimum Solution But Not Always. How To Recognize It?
GRADATION CHANGES AND YOU MUST EITHER CHANGE THE OTHER PARAMETERS OF JMF TO MEET NEW SITUATION (DO YOU KNOW HOW?) OR
NOT CHANGE ANYTHING, BUT THEN YOU MUST KNOW THE ‘THE SAFE LIMITS’ (CAN YOU DETERMINE THEM?)
YOU SIMPLY MUST BE EQUIPPED BY 'KNOW HOW' OR USE ASPHALT EXPERT SYSTEM®© To Figure Out What To Do In Any Given Situation.
“Bituminous paving mixtures are used as surface or base layers in a pavement structure to distribute stresses caused by loading and
to protect the underlying unbound layers from the effects of water. To adequately perform both of these functions over the pavement design life,
the mixture must also withstand the effects of air and water, resist permanent deformation, and resist cracking caused by loading and the environment.
Many factors affect the ability of a bituminous paving mixture to meet these structural requirements. Mixture design, construction practices,
properties of component materials, and the use of additives all play important roles in the resulting structural characteristics of a
pavement. It is also important to recognize the interaction between mixture design and pavement design to arrive at the most cost-effective solutions.
· Changes in the properties of component materials, primarily in the availability of good sources of the two main components—asphalt and aggregate;
· Increased severity of the conditions under which bituminous mixtures are expected to perform, primarily greater tire contact stresses, loads, and load repetitions
The behavior of bituminous mixtures under traffic and environmental conditions is highly complex…”
(Well Formulated and Observed...An Extract From A Group Of Asphalt Researchers, 2002)
PERPETUAL ASPHALT PAVEMENTS - FOR DECADES IN PERFECT SHAPE AND FUNCTION – ARE EVERYWHERE.
ASPHALT EXPERT SYSTEM®© ANALYZED GREAT DEAL OF THEM AND FOUND MANY ‘COMMON DENOMINATORS’ REGARDING ‘SPATIAL’ COMPOSITION.
NO NEED TO INVENT HOT WATER!